A banner made by a local middle school depicting Republican vice presidential candidate, Representative Paul Ryan, at left, and Vice President Joe Biden, at right, hangs on the wall inside the media center ahead of Thursday's vice presidential debate, Wednesday, October 10, 2012, at Centre College in Danville, Kentucky.

If you find yourself moved to prepare for tonight's debate between Joe Biden and Paul Ryan by watching the 2008 vice-presidential debate, your first response will be, "Holy cow, I'd almost forgotten what a nincompoop Sarah Palin is." But after that, you'll be reminded that before he became the shirtless, Trans Am-washing guy so hilariously lampooned in The Onion, Biden was known as one of the most eloquent speakers in his party. He was well prepared for his meeting with Palin; not only did he talk fluidly about a range of issues, but he came armed with an array of factoids that he parceled out effectively and he was ready with practiced responses to most of Palin's criticisms of Obama. The verdict at the time may have been that Palin succeeded by being less than the complete disaster the McCain campaign feared she'd be, but Biden showed himself a more than capable debater.

Perhaps most important, Biden did what he does best, merging detailed policy arguments with emotional, personal content, all delivered in a tone that was often passionate, but nevertheless restrained. And that's what anyone waiting for a Biden gaffe in tonight's debate might be missing: The crazy things Biden sometimes says usually come either when he's shooting the breeze with people or when he gets worked up while delivering a speech; in other words, when he's either too relaxed or too excited. In the formal setting of the debate, Biden should be somewhere in the middle, making a cringe-worthy gaffe unlikely. And there's little chance that he'll arrive as listless as Obama was in the first debate. Vice presidents don't make the front page very often, and this is the biggest stage Biden will have been on in four years, so he'll be motivated.

Before we get to his opponent, we should keep in mind that no matter how well Biden or Paul Ryan does, this debate is unlikely to have an enormous impact on the ultimate outcome of the race. No VP debate has before, not even the 1988 debate between Lloyd Bentsen and Dan Quayle, which featured the most stunning televised meltdown since Dorothy threw water on the Wicked Witch of the West. That said, this may be as good an opportunity for a VP debate to influence the race as you'll see.

It comes at a critical moment, with the lead Obama enjoyed after his convention erased and the race now in a virtual tie. The Obama campaign is surely hoping that Biden will do well enough to reverse the momentum of the last week. As much as I hesitate to put too much stock in "changing the narrative," the media narrative—now all about Obama's collapse and a reinvigorated Mitt Romney—can have a practical effect. Despondent supporters are less likely to donate money or give up a Saturday afternoon to knock on doors. Endless stories in the press about how your campaign is sinking and your opponent is surging keep you from reinforcing the messages that will persuade voters. After a week of stories about Romney momentum, a solid performance from Biden could give the press something new to talk about and revive Democratic enthusiasm.

What we don't know is how Paul Ryan will perform on the biggest night of his professional life. CNN broke the stunning news that Ryan had not called Sarah Palin for advice, which shows some good judgment on his part. But unlike Mitt Romney, who participated in two dozen debates this year and about as many four years ago, Ryan has never been in quite this position before.

Ryan might turn out to be a spectacular debater. But he'll have to defend Mitt Romney at a particularly tricky moment. The newly moderate persona Romney unveiled in the first debate—and the numerous falsehoods he told—could put Ryan in an awkward position. For instance, Romney just took what is by some accounts his ninth different position on abortion, something Ryan would probably rather not talk about. Ryan has already demonstrated that when questioned about the fundamental dishonesty at the heart of Romney's tax plan—the contention that they can lower rates for everyone and pay for the whole thing by closing as-yet-unspecified loopholes for the wealthy—he flounders. And it's hard to blame him, because as William Gale of the Brookings Institution noted, it's tantamount to claiming Romney could drive from Boston to Los Angeles in 15 hours without breaking the speed limit, and there's just no convincing way to explain it. Add in Romney's false declaration in the first debate that his health care plan covers people with pre-existing conditions (it doesn't) and Ryan's own hard-right positions on topics like abortion and Medicare, and the congressman could spend much of the debate defending things that are hard to defend.

This will also be only the second extended look the voters have had at Ryan, after his convention speech was widely panned for its absurd claims and misrepresentations. Ryan can come off as smart and earnest, but he can also remind you of the kid who spent his afternoons in the vice-principal's office telling which kids were smoking cigarettes behind the school. As excited as conservatives were about Ryan being named Romney's running mate, he hasn't brought much value to the ticket so far. If Biden can manage to keep him on his heels, this could be a vice-presidential debate unlike we've seen before—one that matters.

Institutional forces, broad historical trends? Not in the Trump era, where everything is personal.

About the Author

Paul Waldman is a weekly columnist and senior writer for The American Prospect. He also writes for the Plum Line blog at The Washington Post and The Week and is the author of Being Right is Not Enough: What Progressives Must Learn From Conservative Success.